Function start

backend/resources/postgres/postgres.go:22–51

start starts a postgres database instance. If port is 0, then it will choose a random unused port.

(port int, dataDir string, serverLog bool)

// start starts a postgres database instance.
// If port is 0, then it will choose a random unused port.
func start(port int, dataDir string, serverLog bool) (err error) {
	// See -p -k -h option definitions in the link below.
	// https://www.postgresql.org/docs/current/app-postgres.html
	// We also set max_connections to 500 for tests.
	p := exec.Command("pg_ctl", "start", "-w",
		"-D", dataDir,
		"-o", fmt.Sprintf(`-p %d -k %s -N 500 -h "" -c log_checkpoints=off`, port, common.GetPostgresSocketDir()))

	uid, _, sameUser, err := shouldSwitchUser()
	if err != nil {
		return err
	}
	if !sameUser {
		p.SysProcAttr = &syscall.SysProcAttr{
			Setpgid:    true,
			Credential: &syscall.Credential{Uid: uid},
		}
	}

	// It's useful to log the SQL statement errors from Postgres in developer environment.
	if serverLog {
		p.Stdout = os.Stdout
	}
	p.Stderr = os.Stderr
	if err := p.Run(); err != nil {
		return errors.Wrapf(err, "failed to start postgres %q", p.String())
	}

	return nil
}

// stop stops a postgres instance, outputs to stdout and stderr.
func stop(pgDataDir string) error {